Daikin VRV IV RXTQ-TA / RXTQ-TB error code J3
Discharge pipe thermistor abnormality, R2T
Which models this applies to. Outdoor unit
Quick answer
On Daikin VRV IV RXTQ-TA / RXTQ-TB, J3 is a fault. It means discharge pipe thermistor abnormality, r2t. A first thing to check: A failed R2T thermistor.
- Applies to
- Daikin VRV IV RXTQ-TA / RXTQ-TB
- Daikin VRV IV RXTQ heat pump codes · Heat Pump
- Type of code
- Fault
- Urgency: Book a technician
- First safe check
- Check that R2T is clipped to the discharge pipe and that the wire is not chafed against the hot line.
What J3 means on this model
The R2T thermistor on the compressor discharge line has reported a fault. This is the sensor failure code, not the temperature excursion code, and the two have different repairs.
Symptoms you will notice
- Outdoor unit shows J3 and the system stops
- The system will not start
- The system will not recover after a defrost
- The fault followed work on the outdoor unit
Common causes
The code tells you what the control detected, not which part failed. These are the causes we see most often, roughly in order of likelihood:
- A failed R2T thermistor
- A loose or broken wire at the thermistor
- A disturbed connector
- A clip that has come loose from the discharge pipe
- A thermistor whose resistance is out of range
What you can safely check
These are homeowner-level checks. None of them need you to open a live electrical compartment or work on gas.
- Check that R2T is clipped to the discharge pipe and that the wire is not chafed against the hot line.
- Check the connector at the sensor.
- Compare the resistance against the pipe temperature using the resistance chart in the manual.
Do not do these
- ×Do not treat J3 as the same fault as the discharge temperature excursion code. One is a failed sensor and the other is a genuine overheat, and they have different fixes.
- ×Do not work on the connector with the power switch on.
When to call a technician
Worth scheduling, and worth your own checks first
You can usually keep living with this for a short while, but it will not fix itself. Do the safe checks below first, because a tripped switch or a blocked airflow is a five-minute fix that would otherwise cost you a service call.
- The refrigerant circuit is sealed and legally requires licensed handling. Opening it without certification releases refrigerant and can put the whole system in violation of regulation, so a low-pressure or high-pressure fault on this equipment is a call-out, not a weekend job.
- If the appliance has stopped mid-cycle, is making a noise you have not heard before, or smells burnt, stop reading here and call. Those are symptoms of something the fault code does not describe well enough.
A technician job.
What it costs to fix
Parts
Discharge thermistor $30 to $90.
Labor
One to two hours to test and replace.
DIY or technician
A technician job.
Typical US part and labor ranges, 2026. They vary by region, model and contractor, so treat them as a planning figure, not a quote.
Scope of this code
- Code table
- Daikin VRV IV RXTQ heat pump codes
- Models in scope
- Daikin VRV IV RXTQ-TA / RXTQ-TB
- Checked
- Confirm on your own unit
- Find the model number on the data plate, then check this code in the service manual for that model. Manufacturers revise code tables between model years, and a revised board can renumber a fault.